(1) Field of the Invention
The present invention relates to a method and apparatus for winding a wire to form a coil using a hook, in which the wire is inserted into an insert section of a work by means of the hook in which a clamp, for grasping an end of the wire, is rotated relative to the work to carry out the winding of the wire without damage to the wire.
(2) Description of the Background Art
Conventionally, in a case when a wire is wound on a core having a small hole, the wire is inserted into the hole using a hook needle.
In a such a winding apparatus, a hook is used to insert the wire into an insert hole of a work and an end of the wire is grasped by means of a clamp. The clamp then grasps the portion of the wire which has been inserted through the inserting hole and is rotated around the work to form a wire coil.
Such a winding apparatus is exemplified by a U.S. Pat. No. 4,625,927 issued on Dec. 2, 1986.
However, there are disadvantages in the above-described, winding apparatus. For example, since the work has an edge around the inserting hole, the enamel-coated insulating envelope of the wire may be damaged from contact pressure with the edge. Electrical leakage between the wire and core therefore occurs. In a worst case, wire breakage may occur due to contact pressure between the insulating envelope and the edge. For this reason, the possible number of turns of the coil cannot be increased.
In addition, the wire is flexed and deformed by this process and may become kinked. This problem is not easily remedied. If the wire becomes twisted in its intermediate portion, continuing the winding operation to the terminal end of the wire becomes difficult.
Furthermore, since the wire is struck on the edge, the movement speed of the hook cannot be increased to increase the speed of the winding operation.
Since the hook described above conventionally has a diameter of about 0.08 mm, the wire is drawn and struck on the edge by means of a hook having a small diameter. Hence, the insulating envelope of the wire can become damaged and produce electrical current leakage. In addition, since the wire is pressed and struck on the edge which has as the same number as the number of turns of winding, breakage may occur along the wire at any point. For this reason, the drawing speed of the wire by means of the hook cannot become great or deformation or kinking of the wire occurs.